Archive for May, 2009

China’s plan to build dams along the Mekong River poses the greatest threat to the river’s future, according to a United Nations report released yesterday. China is constructing a series of eight dams on the upper half of the Mekong as it passes through high gorges of Yunnan Province, including the recently completed Xiowan Dam, which — at 958 feet (292 meters) high — is the world’s tallest. Its storage capacity is equal to all the Southeast Asia reservoirs combined [AP], according to the report.

The Mekong, which is known as the Lancang in China, is an important source of water, food, and jobs for residents in the river basin, and runs through China, Myanmar, Laos, Thailand, Cambodia and Vietnam. It provides a habitat for rare species of bird and marine life. If the dams move ahead, said the report, the consequences will include “changes in river flow volume and timing, water quality deterioration and loss of biodiversity” [AP]. But Chinese Foreign Ministry spokesman Ma Zhaoxu defended the proposed plans, saying China would give equal attention to hydropower development on transnational rivers and ecological protection [Xinhua].

A new optical storage technique that records in five dimensions could hold up to 10,000 times what a standard DVD can store. The new technology could see a whopping 1.6 terabytes of information fit on a DVD-sized disc [BBC], whereas a DVD now can hold only 8.5 gigabytes and a Blu-ray disc up to 50.

Discs started out storing information in two dimensions and more recently have been stepped up to three. By using gold nanorods [the researchers] were able to add two additional dimensions, one based on the colour spectrum, and the other on polarisation [PhysOrg]. The key for his team was to find a material for the disk that could store this extra information…. That ideal material contains gold, rod-shaped nanoparticles of different sizes and orientations [Nature].

The U.S. government has announced increasing concern over the quality of its Global Positioning System (GPS), which could begin to deteriorate as early as next year, resulting in regular blackouts and failures – or even dishing out inaccurate directions to millions of people worldwide [The Guardian]. The possibility that new satellites would not be launched in time was announced in late April, but the warning was stepped up this week in a government statement that recognized cost over-runs of defence department space programmes [Nature] as part of the problem.

The functioning of GPS relies on a network of satellites that constantly orbit the planet and beam signals back to the ground that help pinpoint your position on the Earth’s surface [The Guardian]. GPS service cannot maintain its level of precision if old satellites wear out before new satellites are launched as replacements, and the ability of the system to provide full coverage could dip below 95% between 2010 and 2014, when the Air Force plans to begin replacing the current block of satellites with a newer generation [Nature], warned the report by the Government Accountability Office.

Early Mars may have been both wet and cold, with average temperatures well below freezing, according to a new study. But researchers also saw signs of the presence of dissolved minerals that would allow for liquid water—the same way salt can melt ice on a road—thus opening up the possibility that the planet sustained life.

Scientists have long been at odds over the history of Mars, debating whether water formed much of its landscape or whether temperatures were simply too cold to have allowed liquid water to flow. But in the new study, published in Nature, researchers used a computer model to show that both could have been possible because fluids containing dissolved minerals would have remained liquid at temperatures well below 273 degrees Kelvin — the freezing point of pure water. “Our results are compatible with Mars lander and orbiter data and with climate modeling, and suggest a cold and wet early Mars” [Reuters], the authors wrote.

Tumors may physically trigger depression by producing chemicals that induce negative mood swings, according to a new study. The research, conducted in rats, allowed for the isolation of “just the physiological effects of the tumors from the psychological effects…. The tumors themselves are sufficient to induce depression” [The Scientist], says lead researcher Leah Pyter.

The new study, published in the Proceedings of the National Academy of Sciences, showed first that rats who had cancer exhibited several behavioral symptoms associated with depression. The researchers gave a forced swimming test to 100 rats, some healthy and some with cancer, and found that the sick rats did not try as hard to escape—a behavior similar to that seen in humans with depression. The sick rats were also less interested in sugar water, which is the the clear preference for healthy rats.

While initial public panic about the swine flu outbreak has largely subsided, the virus continues to spread through our species: The World Health Organization has tallied more than 10,000 cases worldwide, with 80 deaths confirmed. As patterns begin to emerge regarding who gets infected with the H1N1 flu virus, health officials are beginning to map out strategies for a potential wide-spread vaccination campaign.

Young people are particularly prone to infection, researchers say. Preliminary studies of family transmission showed that when one member gets infected, the most likely to follow are those under 18, not parents or grandparents [The New York Times]. The virus’s spread through the young has led to the closing of schools in infection hotspots–Japan is the most recent country to shut school doors–but most cases in young people have not been severe. The people who do get more serious cases that lead to hospitalization have tended to have underlying health conditions like heart problems, lung ailments, immune diseases, and diabetes. Surprisingly, obesity has also emerged as a risk factor.

As early as 1400 B.C., the people of the Andes dug deep to mine the mercury ore called cinnabar, which they crushed to produce a bright red pigment. The pigment, vermilion, was used in ancient Andean rituals and is frequently found adorning gold and silver ceremonial objects in ancient burials of kings and nobles in South America [National Geographic]. While obvious traces of those mines were obliterated by later mining operations run by the Incas and then the Spanish colonists, a clever new study used sediment samples from lake bottoms to uncover evidence of the ancient mining–and the accompanying mercury pollution.

Researchers found that the cinnabar mining started long before the Chavín culture—which Cooke described as “the cradle of complex Andean culture”—peaked, between 800 B.C. and 400 B.C. in central Peru. “The traditional thinking has been that large-scale mining and metallurgy only begins after you get the emergence of large-scale societies that have social stratification and people can specialize in different crafts,” Cooke said [National Geographic]. Instead, Cooke suggests that mining may have encouraged the rise of complex society, as a leader with access to vermilion could have held great sway over a large group of people.

President Obama proposed new fuel efficiency standards today, establishing the first nationwide regulation for greenhouse gases [Washington Post]. The proposal is centered around the strictest plan ever for increasing fuel standards for passenger vehicles, sharply raising pressure on struggling automakers to make more efficient cars and trucks [Reuters]. Under the plan, cars would be required to reach an average efficiency of 35.5 miles per gallon (mpg) by 2016—four years earlier than the deadline imposed by the 2007 energy bill. Light trucks would be required to reach 30 mpg.

The new rules would pose a challenge for car manufacturers: the White House estimates the current average efficiency to be 25 mpg. The new standards would resolve the spat between California and auto manufacturers over implementing the state’s emissions regulations [ClimateWire]. In return for the strict national rules, California will drop its plans to impose strict state-wide standards for fuel efficiency, which had been bitterly resisted by both carmakers and President George Bush. In practice California’s rules tend to override milder national regulations, as it is cheaper to follow them than to produce different vehicles [The Economist].

This morning, 350 miles above the Atlantic Ocean, a tender goodbye took place. Astronauts aboard the Atlantisspace shuttle released the Hubble Space Telescope to conclude the telescope’s fifth and final repair mission. The better-than-new observatory is expected to send back breathtaking images and mind-rattling information about the universe for another five to seven years. As the NASA officials in charge of the telescope put it: “Hubble is now ready to resume its role as humankind’s most powerful eyes on the universe” [AP].

During this mission, Atlantis astronauts spent more than 36 hours over five marathon spacewalks to make upgrades and outfit Hubble with new instruments. These included a panchromatic wide-field camera that should be able to see objects formed just 500 million years after the universe’s birth in the big bang explosion some 13.7 billion years ago [Reuters]. But there were occasional glitches: When a bolt wouldn’t come free on the Sunday spacewalk, astronaut Mike Massimino had to resort to brute force, jerking the railing that it held in place until the bolt snapped. There was also an ill-timed incident this morning involving an antenna.

The Komodo dragon has unusual hunting methods, but it generally gets its meal: The monstrous lizard, which can reach 10 feet in length, lies in wait for prey and then lunges out to deliver a single deep bite, often to the leg or the belly. Sometimes the victim immediately falls, and the lizards can finish it off. But sometimes a bitten animal escapes. Biologists have noted that the lizard’s victims may collapse later, becoming still and quiet, and even die [The New York Times].

This delayed reaction had caused previous researchers to suggest that the dragon kills via blood poisoning caused by the multiple strains of bacteria in the dragon’s saliva. But “that whole bacteria stuff has been a scientific fairy tale,” said Bryan Fry [National Geographic News], lead researcher in a new study. Instead, the dragon uses its sharp, serrated teeth to rend its victim’s flesh while it simultaneously injects a venom that lowers the animal’s blood pressure and prevents blood clotting. Says Fry: “If you keep it bleeding and lower its blood pressure, it’s going to lose consciousness, and then you can tear its guts out at your leisure” [The New York Times].